Work will continue on the development of 252Cf-plasma desorption mass spectrometry for use in biomedical research. The development will involve two classes of molecules which are important for biomedical studies: highly thermally-labile molecules that are unstable at room temperature and are air and light sensitive, and large biomolecules. An aerobic sample preparation method will be developed using prostaglandin precursors as model compounds (particularly peroxides such as HPTE). The study of large biomolecules will continue with emphasis on improving resolution and sensitivity by using the Mamycin reflection principle and introducing post-acceleration to increase detector sensitivity. Work will continue on the 252Cf-PDMS of complex glycopeptides (ristocetin, avoparcin) and bleomycin, to develop an understanding of the relationship between fragmentation patterns and structures. Finally attempts will be made to determine precise masses of molecules up to 500 m/z using a computer-based statistical analysis method to obtain milli mass precision at nominal mass resolution of 1000.